James norman smith



Patented Dec. 4, 1923.

Lfllttil ELECTROLYTlE APPRATUS.

Application filed April 7,

T 0 all whom t may concern.'

lle it known that l, larme NORMAN Siurri-I, a citizen ot the Dominion oi Canada, residing at Toronto, in the county of York, Province ot Ontario, Canada, have invented certain new and uset'ul linprovements in Electrolytic Apparatus; and l do hereby declare the following to be a lull, clear, and exact description ot the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

rlhis invention relates to the art ot' electrolysis. More particularly, it relates to apparatus wherein electrolyzing operations can be effected economically and eXpedi* tiously at relatively high current densities, while the products of electrolysis can be separately recovered in a state ot purity satisfactory for general use. rll`he apparatus may be used, for example, in electrolyzing saline or other solutions, in electrodeposr tion of metals, and in producing oxygen and hydrogen electrolytically.

Considered broadly, the appara-tus et the present invention is of a type generally similar to that described in the col-pending application of Clark & Smith, Serial No. 4:59292, tiled April 7, 1921, and can be employed in analogous ways and for similar purposes. In the speciiic illustrative enibodiment oi the broad invention described in said application of Clark L- Smith, a pair ot cooperating hollow or tubular electrode members are mounted in axial alinement iu opposite walls ot a suitable casing or container, the adjacent ends ot said tubular electrode members providing annular active electrode surfaces spaced apart only a small distance, usually not more than oneiiourth ot' an inch at the most, and still better as little as onewtenth of an inch or even very much less. In that particular1 torni ot apparatus, electrolyte is forced to flow radially inward across the annular slot like electrolyzing zone thus provided between the electrode members of the couple, at a velocity suiiiciently high to prevent substantial intermingling ot the anodic and cathodic products in said zone; and as the inwardly flowing body ot electrolyte `leaves the annular electrolyzing zone, it impinges upon a separator device which is adapted and arranged to divide the inilowing` electrolyte into `anolyte and catholyte portions, from which anodic and cathodic products ieri. serial no. Masai.

oi electrolysis can be separately recovered. Most dcsirably no porous separating diaphragm is employed, the space between the active electrode surfaces proper being unobstructed.

The present apparatus has some features in common with the construction just described, but involves certain further developments offering substantial practical advantages. @ne such development is the provision oi" means whereby the electrolyte travels in separate paths not only after {iowing through the electrolyzing Zone, but also betere it reaches said Zone. lin a practical embodiment ci' the present invention, the arrangement may be generally described as comprising separator or partition means having a relatively narrow' elongated gap therein adjacent to and in registry with the elongated active electrode surfaces between which the electrolyzing zone is comprised, together with provision tor causing electrolyte to flow in the same general direction on both sides of said sepa rater means and across the active electrode surfaces, the flow on both sides ot said separator mea-ns being substantially parallel through 'the electrolyzing zone. is in the case ot the apparatus disclosed in the aforesaid Clark In Smith application, it is preferred to operate without the use of the usual porous separating diaphragm, the omission ot such diaphragm making it possible to bring the active electrode surfaces very close together and thus to greatly reduce the resistance ci the current path between the electrodes. The resistance may be still further reduced by operating at relatively high electrolyte temperatures. lli/here the electrolyte is supplied under pressure, which is often desirable in practice, the operating temperatures may exceed the boiling point of the electrolyte at atmospheric pressure.

For the sake ot a concrete example, a practical form oit apparatus embodying the broad principles oi the invention will be described iu connection with the accompanying drawings, in which Figure l is a view in central vertical section ot apparatus embodying the invention; and

Figure 2 is a horizontal section on the line 2-2 of Figure l.

Referring to the drawings, 10and l1 are sections of a heavy walled casing having` llt) cooperating peripheral flanges 12 between which is clamped the outer marginal portion of an annular separator plate 13 to be referredy to more fully hereinafter. The assemblage is held together by any suitable means such as bolts 14 which may be encased in insulating bushings 15; and the joints between the annular plate 13 and the casing flanges are maintained liquid tight by means of suitable packing 16. Mounted in op posite walls of the casing and in axial alinementare cooperating tubular electrodes 17 and 18, 17 being an anode inthis instance and 18 a cathode. Each of the electrodes is electrir cally insulated from the casing wall through which it passesfas indicated at 19, and is externally threaded to accommodate nuts 2O and 21, one of which is arranged inside the casing and the other outside, said nuts cooperating to hold the electrode firmly in position while at the same time allowing it to be adjusted in an axial direction.

The adjacent ends of the electrode Hare outwardly as indicated, to provide closely adjacent active anode and cathode surfaces 22, 23', which may be substantially plane and parallel, the planes of said annular surfaces being substantially at right angles to the Vcommon axis of the two electrodes. Most desirably, said active annular electrode surfaces 22, 23, are very close together, say within one-tenth of an inch of each other or even considerably less. Adjacent the outer periphery of the annular slot-like passage thus formed between the cooperating electrodes of the couple is the inner edge 24 `of Vthe annular separator plate 13 before mentioned. It is advantageous to have this inner edge 24substa-ntially in line with and between the outer peripheral edges of the active electrode surfaces` 22, 23. The plate 13 Vmay be ofinsulating material, as shown; in which case it serves also to insulate the casing sections 1() and 11 from each other and renders optional the employment of insul'at ing material 19 aroundthe electrodes'where they passl through the casing walls.

It is also desirable to provide separator means within the tubularY electrode assemblage for'guidingliquid in separate paths corresponding to those outside said assemblage Vand communicating respectively therewith through the electrolyzing zone. To this end, a disc 25, composed in this instance of' insulating material and having a peripheral separating edge which lies substantially in the plane'of the opposed edge of the outer separator member 13, is supported in any suitable manner within the combined tubular electrode assemblage, the disc edge being y concentric with they annular active electrode surfaces and substantially in registry with the inner periphery ofthe active electrode surfaces. In the particular construction here illustrated, the adjacent edges of the separator' members 13 and 25 are shown beveled thin; but while this is desirable, it is not essential to the invention .in its broader aspects. It is usually advantageous that the edge upon which the electrolyte flow in1- pinges be fairly thin. This arrangement leaves thc annular active electrode surfaces directly exposed to each other, or in other words the passage between them is unobstructed. The disc 25 and the annular plate 13, having the annular openingl or gap be tween their adjacent edges, may be broadly termed separator means, providing separate pathsfor flow of anolyte and catholvte. respectively, to, through, and away from the narrow electroly'liingl zone where the two layeriform bodies of liquid moving swiftly in parallel are momentarily in Contact. ln the construction here illustrated, the disc 25 is held between conoital members or Vheads 26, 27, which curve oi taper in opposite directions from the disc 25 Vinto stems 28, which in turn are held in the axis of thc electrode assemblage by any suitable means, not shown. It will be seen that the surfaces of these heads diverge gradually from the inner walls of the respective electrode members in a direction away from the clertrol-vzing zone. In the arrangement here shown. the head 2G has a threaded stud or projection 29 extending through a central aperture in the disc 25, said stud being engaged by a nut 30 of insulating material which is cxternally threaded for connection to the other head 27. The casing is provided on opposite ides of the plate 13 with discharge outlets ai, 32.

ln employing the apparatus above described for the generation of oxygen and hydrogen from water` for example` current at the proper electrolyzing voltage is supplied to the electrodes 17 and 18 in any suitable manner, the electrode 17 being the anode and the electrode 1S beingr the cathode, and an aqueous electrolyte. auch as a solution of caustic soda or caustic potash, may be fed in, preferably under pressure. through both electrodes in the direction of the indicating arrows. Ordinarily the pressure on the electrolyte thus fed in will be the same for both electrodes. The velocity of How increases gradually owingl to the contraction of the annular passages foruied between the curved inner walls of the electrodos and the curved surfaces ol the detlecting or directing device 25. 26, '27. the contraction being ,\,;roulest and the maximum velocity therefore be` ing attained where the streams of elect rolyto become substantially parallel and tlow outwardly through the unobstructed passage between the active electrode surfaces. The width of this annular passage or electrolyz ing zone measured parallel to the active elec* trode surfaces, that is. in the direction of the electrolyte ow, is relatively small; so that during the brief interval involved in crossing this Zone, the rapidly flowing streams or layers of electrolyte do not internnngle peri ceptibly and the anodic and cathodic products ot electrolysis do not interditfuseinaterially. Consequently separate flow ot anolyte and catholyte, respectively carrying oxygez'i and hydrogen swept from the active electrode surfaces, is continued and maintained by the action oi the dividing edge 24C ot the separator plate 13 which the outwardly 'flowing electrolyte encounters as it leaves the electrolyzing Zone. Atter the electrolyte impinges upon this dividing edge, its velocity of tloyv immediately falls. Arnolyte and oxygen are discharged through out let 3l, While catholyte and hydrogen are discharged through outlet 32. @xygcn and hydrogen may be separated `from the anolyte and catholyte, respectively, in any ivell Vknown or suitable api'raratus tor this pur pose, one suitable type, referred to for the salte ot a concrete example hut unnecessary to illustrate here, being disclosed in the copending application of Clark & Smith aforesaid.

As betere stated, the pressure on the elecn trolyte on hoth sides ot the partition means may he the same. However, under some conditions, or tor certain purposes, it may be desirable to operate with greater pressure on one side than on the other. For enample, Where it is desirable to secure partic- -ularly pure oxygen, the pressure on the oxygen and anolyte side may he somewhat greater than on the hydrogen and catholyte side, thus serving further to guard against accidental ditlusionoi hydrogen in the electrolyzing zone across into the oxygen side. The excess pressure on the oxygen side supplements the natural. buoyancy ot the hydrogen in the particular arrangement ot the apparatus here illustrated, wherein the cathode is disposed above the anode, and the result is production ot oxygen having a par ticularly high degree ot purity and freedom from hydrogen.

`lnstend ot having the partition means arranged horizontally as illustrated in Fig. 1, it is sometimes desirable to have such partition means arranged. substantially vertically, which can be attained, for example, by turning the apparatus illustrated in Fig. l angularly through 900 in the plane o t the drawing. lllhen the apparatus is ot the specific construction shown, this rotation should be counterwclochwise in order to bring the discharge outlets gas-laden anolyte and cathor lyte near the upper part of the casing in that position. i

lt will be noted that While, in ahove describing the operation of the apparatus, it was speciied that the electrolyte was introduced into the electrodes, flowing to- Ward the central portion ot the apparatus and thence outwardly through the electrolyzing Zone into the casing, this direction ot 'flow may yadvantageously be reversed under some conditions, this reversal in direction et flow being permitted hy the illustrated. arrangement et the apparatus parts. ln any case the velocity ot the electrolyte diminishes considerably after passage through the electrolyzing Zone, thus taroring coalescence ot the evolved gas particles into buhhles which can be readily seg-iarated from the accompanying anolyte and catholyte, respectively. The ability to dispense with a porous separating diapl` anni, coupled with the provision tor torcing the electrolyte to tloiv at su'tliciently high velocity across the active electrode surfaces, makes it possible to operate at relatively high current densities. Operation l0 amper-es or more per square inch of projected electrode area, or et the cross sectional area ot the current path, 'is easily attainable Without requiring an operating voltage in excess ot `those commonly einployed heretofore in electrolyzing Water. rllhe sivitt tloiv oit electrolyte across the ad tive electrode surtaces svveeps away 'the tino particles as Ylast as they are generated and thus prevents excessive polarization; While the same agency keeps the active electrede surtaces clean and tree troni accumulations due to corrosion, and they are theretore eiltectire at all times. rllfhe axial adjustabih'-y oi the electrodes tacilitates main ing the electrodes the proiiier distance apart it'or best operation; and it also provides tor accurate adjustment; between the relative positions et the electrodes and the double separator or partition means Whereby proper direction and division ot the 'flowing electrolyte into separate paths is etccted. 'lho inner separator device may also be axially adjustable, any suitable .mount-.ing thereof that will permit this beinrr amaropriate tor the purpose. such as that .illustrated in the aforesaid application et Clark t Smith.

Another ad antagc ot the present are rangement is that it enables the anolyte and catholyte to he lrept circulating in entirely independent systems both Within and outside et the s crater unit, The` connninfling ot g s e anolyt-o and catluiljvte, and the return oi" this comminglod electrolyte, instead ot gas-tree anolyte and catholyte separately.. to the generator unit 'tor further passage through the electrolysing Acne, is not precluded, however.

lllhere recovery oi the anod'cy and cathn odio products separately is not essential, that portion ot the separator nie-ans on the cilluent 4side o't the electrolyzing` zone may be omitted While still realizing the advantages ot the invention in part. Other changes in details ot construction and ar rangement may be made Without departing from the scope of the broad invention.

Unless otherwise specified, vthe term annular as employed in the appended claims is to be understood in a broad sense to include Vnot only circular annuli, but other curved annuli, polygonal annuli, and the like. Moreover, it is to be understood that the invention is'not limited to apparatus in whichv the electrodes are annular even in the broad sense mentioned.

vThe process carried.Y out in the apparatus ierein disclosed, is not claimed herein, butis. the subject mattei' of a copending application for patent of Farley G. Clark entitled Method of electrolysis, filed on even date herewith and given Serial Number 459,291.

What I claim is: f

l. Electrolyticapparatus comprising` the combination, with cooperating active anode land cathode surfaces disposed in closely spaced relation and defining an electrolyzing zone of small transif'erse Width measured par llel to said surfaces, of conduit means arrangedto direct flow of electrolyte to Ward, across. and away from said zone in streams which contact with one another only While crossing said Zone.

2. Electrolytic apparatus comprising the combination, With cooperating active anode and cathode surfaces disposed in closely spaced relation and defining an electrolyzing` zone of small transverse Width measured parallel to said surfaces, of'an electrolyte supply, and means operative to guide flow of electrolyte in separate streams into contact and substantial parallelism with said active surfaces. Y

3. Electrolytic apparatus comprising the combination, with cooperating active anode and cathode surfaces having a free passage between them, of means arranged to conduct separate streams of electrolyte to one side kof said passage and to direct said streams across the respective electrode surfaces, and means on the other side of said passage arranged to receive the etliuent streams and maintain them separate.

4. Electrolytic apparatus comprising the combination, with separator'means having an elongated opening or gap therein, of cooperating electrode members disposed on opposite sides of said separator means and in registry with said opening, and means for passing streams of electrolyte on oppositesides of said separator means across said opening between said electrode members.

Electrolytic apparatus comprising the combination, With separator means having an elongated opening or gap therein, of cooperating electrode members disposed on opposite sides of said separator means and in registryV with said opening, and means for forcing electrolyte to flow rapidly in the same general direction on opposite sides of said separator means and in parallel across said opening between said electrode members.

6. Electrolytic apparatus comprising the combination, With separator means having an elongated openingr or gap therein, of cooperating electrode members disposed on op posite sides of said separator means and in registry with said opening, and means for forcing electrolyte to llow rapidly in the same general direction. on opposite sides of said separator means and in parallel across said opening bet-Ween said electrode menibers. the relative positions of said electrodes and separator means being adjustable.

7. Electrolytic apparatus comprising the combination, with cooperating annular anode and cathode surfaces spaced. apart to provide an annular passage.y of conduit means arranged to direct electrolyte through said passage and across the electrode surfaces in substantially parallel streams.

S. Electrolytic apparatus comprising the combination, with cooperating annular anode and cathode surfaces spaced apart to provide an annular passage, of conduit means arranged to direct electrolyte through said passage and across the electrode surfaces in substantially parallel streams, and conduit means arranged to receive said parallel streams as they leave said passage.

9. Electrolytic apparatus comprising the combination, ivith a casing, of cooperating tubular electrode members coaxially mounted in opposite Walls of said casinar and hav ing their inner ends closely adjacent but spaced apart to provide an annular electrolyzing zone, a separator device mounted. centrally with the assembled electrode members and having` tapered portions extending oppositely from the vicinity of said zone into said electrode member. between each of Which tapered portions and thc inner wall of the corresponding electrode member is formed an annular conduit which is coustricted adjacent said electrolyzing zone, the tivo conduits thus formed curving radially outward and merging substantially at the inner periphery of said elcctrolyzing zone, an annular separator device having its inner periphery located substantiallv at the outer periphery of said electrolyzing zone and substantially in the saine plane as the merger line of said conduits. and ciniduit means opening into said casing on opposite sides of said partition device.

l0. Electrolytio apparatus comprising the combination, with a casing composed of cooperating langed sections, of cooperating tubular electrode members coaxially mounted in opposite Walls of said casing, the inner ends of said electrode members being flared and closely adjacent but spaced apart llli') to provide an annular electrolyzing Zonena separator device mounted centrally Within said electrode members and having a thin peripheral edge located intermediate the same and closely adjacent the inner periph ery of said zone, said separator device tapering in opposite directions -lz'roin said edge and forming with the inner Walls of the respective electrode members annular conduits which narrow toward said edge, an annular partition marginally clamped between the flanges oi? the casing sections, the thin inner periphery oit said partition being closely adjacent the outer periphery olf said Zone and in substantially the same plane as the said peripheral edge ot said separator device, and separate conduits opening into said casing on opposite sides of said partition.

1l. Electrolytic apparatus comprising the combination, with cooperating electrodes having surfaces disposed in closely spaced relation and detining an electrolyaing zone between them, of guiding Walls cooperating with said electrodes to direct tlovv oielectrolyte in a plurality of streams to and across said electrolyzing zone.

12. lllectrolytic apparatus comprising the combination with cooperating electrodes having active electrode surfaces disposed in closely spaced relation and delining an electrolyzing zone between them, of tivo conduit means on one side ot said electrolyaing sone arranged to direct loiv of electrolyte in two separate streams to said electrolyzing zone and in substantial parallelism. across said Zone, and two conduit means on the opposite side o'l said zone arranged each to receive one oit' said streams oi" electrolyte and to deliver the same from said apparatus.

ln testimony whereof l hereunto ardita my signature.

JAMES NURMAN tillltllllll 

